Vapor generator



Dec. 5, 1967 v w.'|. SIGNELL 3,356,076

' VAPOR GENERATOR I Filed Feb. 2, 1966 I 2 Sheets-$heet 1 INVENTOR. WARREN IVAR SIGNELL W afi 7/m 1 li ATTORNEY Dec.5, 1967 w. I. SIGNELL 3,356,076

VAPOR GENERATOR Filed Feb. 2, 1966 2 Shets-Shiaet v /u 1/ 4 I INVENTOR.

WARREN IVAR SIGNELL BY 61M ATTORNEY United States "Patent ()fitice 3,356,076 Patented Dec. 5, 1967 3,356,076 1 1 VAPOR GENERATOR Warren Ivar Signell, Livingston, NJ., assignor to Foster Wheeler Corporation, New York, N.Y., a corporation of New York Filed Feb. 2, 1966, Ser. No. 524,561 7 Claims. (Cl. 122-480) This invention relates to vapor generators and more particularly to vapor generators having a superheater and reheaterand means for controlling the flow of combustion gases through said superheater and said reheater.

In marine applications of vapor generators, particular problems exist as to. reheat. These problems include reversing and port operations during which there is no steam flow throughthereheater. Also, a reduction in steam temperature from the superheater may be required to protect the main engine during a prolonged load in the astern turbines. Furthermore, a wide range of steam temperatures is often required in marine operations. It is also important that the vapor generator utilized be as simple in construction as possible and be as reliable as possible in operation.

Therefore, it is an object of this invention to provide a vapor generator having a superheater and a reheater with means for controlling the flow of-gases through said superheater and reheater.

It is another object of this invention to provide a vapor generator which combines simplicity of construction and reliability of operation.

- The vapor generator in accordance with the present invention has. a single combustion chamber with a laterally adjacent bank of steam generating tubes extending between a steam drum and a water drum. I Just beyond the laterally adjacent bank is a division wall which extends parallel to the longitudinal axis of the drums and separates the furnace into an inner radiant chamber and an outer convection chamber. A by-pass wall which is vertically oriented separates the outer convection chamber into a' by-pass compartment and a heater compartment, The heater compartment is substantially larger than the by-pass compartment and contains a superheater bank toward its lower end. A cavity is located directly above the superheater bank and above the cavity is a reheater bank. An opening in the by-pass wall permits flow of combustion gases around the reheater.

In the smaller compartment below the opening in the by-pass wall is a superheater control damper preferably with a superheater by-pass economizer directly beneath it. Above the opening in the by-pass wall is a reheater control damper preferably with a reheater by-pass economizer directly beneath it.

7 At the top of the larger compartment is a shut-off damper and a cooling damper. Gases passing through either the smalleror larger compartment flow through an economizer to a stack.

' By closing the reheater shut-off damper and opening the reheat control damper, the flow of gases is by-passed around the reheater. By also opening the cooling damper, cool air from the windbox is forced over the reheater to insure adequate cooling without cooling fluid passing through the reheater.

The particular features and advantages which characterize the invention will be understood from the following description when considered in conjunction with the accompanying drawings forming a part thereof and in which:

FIGURE 1 is a sectional side elevation partially broken away showing a vapor generator in accordance with this invention.

FIGURE 2 is a cross-sectional view along line 2-2 of FIGURE 1.

The boiler shown in FIGURE 1 is a single furnace water marine boiler having a setting 11 comprising two side walls 13, 15, a rear wall 17, a front wall 18, a floor 19, and a roof 21. A vapor-liquid drum 23 in the roof 21 is connected to a liquid drum 25 by a bank of boiler tubes 27 arranged between an inner radiant chamber 29 and a division wall 31. The two side walls 13, 15, the front wall 18, the floor 19, the roof 21 and the division wall 31 are all of fin-tube construction. A floor header 32 is'connected to risers (not shown) so as to provide circulation to the liquid vapor chamber 23. The single exception to the use of fin-tube construction is a vestibule 24 between the rear wall 17 and a partition 26.

Burners 34 are located in the roof 21. To accommodate the trend to operation with reduced excess air, they are preferably arranged in a single row and widely spaced. This assures optimum air distribution to the burners and uniform gas distribution throughout the boiler.

Across the bottom of the division wall 31 is an opening 33 through which the products of combustion flow into an outer convection chamber 35. The opening 33 is provided by elimination of the fins and spacing the tubes apart as shown in FIGURE 1. The flue chamber 35 is partitioned by a fin-tu'be by-pass wall 37 into a by-pass compartment 39 and a heater compartment 41. The by-pass compartment 39, as shown in FIGURE 2, is substantially smaller than the heater compartment 41. Both compartments 39, 41 are vertically-oriented as is the by-pass wall 37.

Located toward the lower end of the heater compartment 41 is a superheater 43-which preferably is of the sinuous type running horizontally between an inlet header 45 and an outlet header 47. The superheater 43 is preferably arranged With a lower main section 49 and an upper section 51 of substantially smaller capacity than the lower main section 49. 'Iheinlet header 45 is connected to the lower end of the lower main section 49 and the outlet header 47 is connected to the upper end of the upper small section 51. In this way, the superheater 43 is arranged for parallel flow to assure minimum metal temperatures. Vapor to be superheated enters a superheater supply conduit 50 at a drying inlet 52 located in the vapor-liquid drum 23. The conduit 50 is connected to the inlet header 45. i

A large cavity 53 is provided between the lower main section 49 and the upper section 51, and adjacent this cavity 53 there is an opening 55 in the by-pass wall 37. The opening 55 is also provided by elimination of the fins and spacing of the tubes. Above the upper small section49 of the superheater 43 is a reheater 57. The reheater 57 has a reheater outlet header 59 connected to the lower end and a reheater inlet header 61 connected to the upper end resulting in counter flow. The large cavity 53 permits the gas leaving the lower main section 49 of the superheater 43 to by-pass the upper small section 51 and the entire reheater 57. In this way, the reheater 57 is screened by the upper superheater section 51 from any gas eddy currents when steam flow stops while automatically achieving a slight reduction in the ,superheat temperature for astern and port operations. v

The opening 55 in the by-pass wall 37 provides independent control of the superheater 43 and the reheater 57. The opening 55 and the upper end of the by-pass compartment 39 is designed to carry the gases with the same draft as the reheater 57 itself. Thus, there is no increase in draft loss when maneuvering and there is no need for controlling forced draft fan speed in any special way.

Located in the by-pass compartment 39 below theopening 55 in the bypass wall 37 is a superheater control damper 63. The superheater control damper 63 is formed from a plurality of individual vanes 62. Directly below the superheater control damper 63 is a superheater economizer 64 to limit the gas temperature exiting through the by-pass compartment 39. Located in the by-pass compartment 39 above the opening 55 is a reheater by-pass economizer 65 also used to limit the temperature of the gas passing through the by-pass compartment 39. Above the reheater by-pass economizer 65 is a reheater control damper 67 also including a plurality of individual vanes 62.

The top of the heater compartment 41 narrows to an opening 69 in which a shut-01f damper 71 having several individual vanes 62 is located. As best seen in FIGURE 2, both the opening 69 and the upper end 72 of the by-pass compartment 39 discharge into a common space 73. On the top of the heater compartment 41 a windbox 75 is located. An air passageway 77 is provided between the heater compartment 41 and the windbox 75. Located in the air passageway 77 is a cooling damper 79 also formed of several individual vanes 62. The cooling damper 79 and the shut-off damper 71 are preferably located on a common shaft 80 with the two dampers 71, 79, ninety degrees out of phase with one another. In this way, when the shut-off damper 71 is closed, the cooling damper 79 must be open, permitting cool air to flow over the reheater 57 preventing burnout. Similarly, when the reheater shut-off damper 71 is open, the reheater cooling damper 79 must be closed.

At the opening to the space 73 an economizer S1 is located. The economizer 81 has an inlet header 83 connected to the lower end of the economizer 81. The upper end of the economiz'er 81 is connected to the steam drum 23. Feedwater is supplied to the superheater by-pass economizer 64 at inlet header 85. The superheater by-pass economizer 64 is connected to the reheater by-pass economizer 65 which in turn feeds the economizer 81 through the inlet header 83.

The superheater 43 and the reheater 57 are slightly oversized to permit a small amount of gas to by-pass at all times. This eliminates the requirement for the superheater control damper 63 and the reheater control damper 67 to be gastight.

In operation, whenever there is vapor flow in the reheater 57, the shut-off damper 71 is maintained in a wide open position and the cooling damper 79 is closed. The superheater control damper 63 and the reheater control damper 67 both modulate independently of one another to maintain the desired outlet temperatures from the superheater 43 and the reheater 57. When v'apor fiow through the reheater 57 is stopped, the reheater control damper 67 is first opened wide. Then the shut-off damper 71 is closed and the cooling damper 79 is opened to stop the flow of hot gases and introduce cool air over the reheater 57. The superheater control damper 63 continues to modulate to maintain the superheater temperature.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. A vapor generator comprising:

a setting having a furnace chamber therein;

means for firing said furnace chamber thereby producing combustion gases;

'an upper liquid-vapor drum and a lower liquid drum disposed in said setting; vapor generating tubes communicating at one end with the liquid-vapor drum and at the other end with the lower liquid drum;

a division wall extending between the upper liquidvapor drum and the lower liquid drum and defining an opening along its lower end to permit the flow of combustion gases therethrough, said division wall separating said furnace chamber into an inner radiant chamber wherein said means for firing and said vapor is generating tubes are located and an outer convection chamber;

a by-pass wall vertically oriented within said outer convection chamber to separate said outer convection chamber into a by-pass compartment having a by-pass discharge opening at its upper end for discharging combustion gases and a heater compartment having a heater discharge opening in its upper end for discharging combustion gases;

a superheater located in the lower portion of said heater compartment, said by-pass wall having an opening therein above at least a substantial portion of said superheater;

a reheater located above said superheater and above said opening in said by-pass wall within said heater compartment;

a superheater control means for controlling the flow of gases through the portion of the by-pass compart ment below the opening in the by-pas's wall and through the superheater bank below the opening in the by-pass wall; and

a reheater control means for controlling the flow of gases through the portion of the by-pass compartment above the opening in the by-pass wall and through the reheater bank.

2. A vapor generator according to claim 1 wherein said superheater control means includes a damper means in said by-pass compartment below said opening in said bypass wall.

3. A vapor generator according to claim 1 wherein said reheater control means includes a damper means in said by-pass discharge opening and a damper means in said heater discharge opening.

4. A vapor generator according to claim 2 wherein said reheater control means includes a damper means in said by-pass discharge opening and a damper means in said heater discharge opening.

5. A vapor generator according to claim 4 wherein said heater compartment includes an air opening in its upper end communicating with a source of cool air, a cooling damper means being located in said air opening to open and close said air opening.

6. A vapor generator according to claim 5 including means for actuating said damper means in said heater discharger opening and said reheater cooling damper ninety degrees out of phase With one another so that said cooling damper is open when said heater damper is closed and said cooling damper is closed when said heater damper is open.

7. A vapor generator comprising:

a setting having a furnace chamber therein;

means for firing said furnace chamber thereby producing combustion gases;

an upper liquid-vapor drum and a lower liquid drum disposed in said setting;

vapor generating tubes communicating at one end with the liquid-vapor drum and at the other end with the lower liquid drum, said vapor generating tubes extending substantially vertically within the setting;

a division wall extending between the upper liquidvapor drum and the lower liquid drum on the outside of said vapor generating tubes and having a major upper portion which is a solid barrier and a minor lower portion with openings therein to permit the flow of a combustion gases therethrough, said division wall separating said furnace chamber into an inner radiant chamber wherein said means for firing and said vapor generating tubes are located and an outer convection chamber;

a bypass wall being vertically oriented within said convection chamber and separting said convection chamber into a by-pass compartment and a tube-bank compartment, said by-pass compartment having a by-pass discharge opening at its upper end for discharging combustion gases and said tube-bank compartment having a main discharge opening in its upper end for discharging combustion gases, said tube-bank compartment further having an air opening in its upper end communicating with a source of cool air, said by-pass compartment being smaller than said heater compartment;

main superheater located in the lower portion of said tube-bank compartment, said by-pass Wall having an opening therein above said main superheater bank;

secondary superheater bank, substantially smaller than said main superheater located in said tube-bank compartment directly above said opening in said bypass wall;

reheater bank located directly above said secondary superheater bank within said heater compartment; superheater control damper located Within said 'bypass compartment below said opening in said by-pass wall;

superheater by-pass economizer located in said bypass compartment beneath said superheater control damper;

reheater by-pass economizer located in said by-pass compartment above said opening in said by-pass wall; reheater by-pass damper located in said by-pass compartment directly above said reheater by-pass economizer;

a reheat shut-off damper located in said main discharge opening to open and colse said main discharge opena reheat cooling damper located in said air opening to open and close said air opening, said reheat cooling damper and said reheat shut-oh damper being adapted to operate ninety degrees out of phase with one another whereby said reheat cooling damper is open when said reheat shut-off damper is closed and said reheat cooling damper is closed When said reheat shut-ofi damper is open;

a combustion gas discharge means communicating with said main discharge opening and said by-pass discharge opening; and

an economizer for preheating feedwater to said liquidvapor drum located within said combustion gas dis charge means.

References Cited UNITED STATES PATENTS 2,092,299 9/1937 Black et a1. 122480 X 2,776,647 1/ 1957 Hawley 122-480 3,105,469 10/1963 Fikenscher 122480 25 KENNETH W. SPRAGUE, Primary Examiner. 

1. A VAPOR GENERATOR COMPRISING: A SETTING HAVING A FURNACE CHAMBER THEREIN; MEANS FOR FIRING SAID FURNACE CHAMBER THEREBY PRODUCING COMBUSTION GASES; AN UPPER LIQUID-VAPOR DRUM AND A LOWER LIQUID DRUM DISPOSED IN SAID SETTING; VAPOR GENERATING TUBES COMMUNICATING AT ONE END WITH THE LIQUID-VAPOR DRUM AND AT THE OTHER END WITH THE LOWER LIQUID DRUM; A DIVISION WALL EXTENDING BETWEEN THE UPPER LIQUIDVAPOR DRUM AND THE LOWER LIQUID DRUM AND DEFINING AN OPENING ALONG ITS LOWER END TO PERMIT THE FLOW OF COMBUSTION GASES THERETHROUGH, SAID DIVISION WALL SEPARATING SAID FURNACE CHAMBER INTO AN INNER RADIANT CHAMBER WHEREIN SAID MEANS FOR FIRING AND SAID VAPOR GENERATING TUBES ARE LOCATED AND AN OUTER CONVECTION CHAMBER; A BY-PASS VERTICALLY ORIENTED WITHIN SAID OUTER CONVECTION CHAMBER TO SEPARATE SAID OUTER CONVECTION CHAMBER INTO A BY-PASS COMPARTMENT HAVING A BY-PASS DISCHARGE OPENING AT ITS UPPER END FOR DISCHARGING COMBUSTION GASES AND A HEATER COMPARTMENT HAVING A HEATER DISCHARGE OPENING IN ITS UPPER END FOR DISCHARGING COMBUSTION GASES; A SUPERHEATER LOCATED IN THE LOWER PORTION OF SAID HEATER COMPARTMENT, SAID BY-PASS WALL HAVING AN OPENING THEREIN ABOVE AT LEAST A SUBSTANTIAL PORTION OF SAID SUPERHEATER; A REHEATER LOCATED ABOVE SAID SUPERHEATER AND ABOVE SAID OPENING IN SAID BY-PASS WALL WITHIN SAID HEATER COMPARTMENT; A SUPERHEAD CONTROL MEANS FOR CONTROLLING THE FLOW OF GAGES THROUGH THE PORTION OF THE BY-PASS COMPARTMENT BELOW THE OPENING IN THE BELOW BY-PASS WALL AND THROUGH THE SUPERHEATER BANK BELOW THE OPENING IN THE BY-PASS WALL; AND A REHEATER CONTROL MEANS FOR CONTROLLING THE FLOW OF GASES THROUGH THE PORTION OF THE BY-PASS COMPARTMENT ABOVE THE OPENING IN THE BY-PASS WALL AND THROUGH THE REHEATER BANK. 